Vibration isolator



July 18, 1950 E. PIETz VIBRATION IsoLAToR' Filed March 8, 1947 M )lv/V747.

Inventar Ervin -Pz'elz gem" Patented July 18, 1950 vrBRA'rIoN rsoLAToR Ervin Pietz, Medford, Mass., assigner to L. N. Barry Co., Inc., a corporation of Massachusetts Application March 8, 1947, Serial No. 733,276 9 claims. (Cl. 248-358) My invention relates to flexible mountings known as isolators or absorbers, which are used to prevent or reduce the transmission of vibration impact or noise between structures which must be mechanically connected; For example, isolators are used for mounting machines or devices which create disturbances likely to cause misoperation or deterioration of adjacent instruments or equipment. Examples falling in this category are; motors, fans, solenoid actuated devices, and other apparatus whose operation sets up dynamic forces.

Another application is for mounting delicate apparatus that must be protected from vibrations and impacts which are generated by adjacent machinery. A primary application in this category is for mounting instruments and electronic equipment in airplanes. It is also desirable to mount phonograph pickupsA on vibration isolators to prevent vibration and noise feeding back from the speaker to the pick-up. Vacuum tubes, condensers, and other components of electronic equipment are commonly mounted on vibration isolators both to protect the components from damage and to prevent misoperation which results from sudden movement of the component.

My invention utilizes rubber in ilexure `as contrasted to rubber in shear or compression as used in other types of isolators. The use of rubber in lexure makes possible the largestatic deflections required to isolate loW frequency vibrations. It is also possible by using rubber in flexure to obtain a relatively low stiffness in all directions to isolate the vibrations impressed from many sides.

An object of my invention is to provide a vibration isolator which is capable of'withstanding relatively large static deflections so as to be useful for isolating very low frequency vibrations.

Another object of my invention is to provide a vibration isolator capable of supporting' very light loads and whose size is very small to enable its use in the small spaces encountered with' light weight equipment.

Another object is to provide a vibration isolator which may be conveniently attached to the adjacent structures without making it necessary to use the costly manufacturing operations necessary to bond metal to rubber. 'Ihe resulting isolator is, therefore, characterized by its` low cost compared with the usual bonded type isolators.

1 A further object is to provide a vibration' isolator which may be made adaptable to a wide range of mounting conditions and loads.

Another object of my invention is to provide a 4vibration isolator'v which may be conveniently assembled without the use of bolts, nuts, or other locking means.

A further object is to provide an isolator which may be used for securely locking the supported structure in place kduring service conditions but which structure may be easily and conveniently removed when desirable for servicing or other purposes.

A still further object is to provide a vibration isolator which may be used for attaching a supported structure to` a ysub-adjacent supporting structure without requiring access to the lower side of the supporting structure.

A still further object is to provide a vibration isolator which maybe easily and conveniently attached to a wooden supported structure such as is commonly used in phonographs.

Other` objects and'advantages of my invention will be apparent from the following detailed description and accompanying drawings:

Figure 1 is a vsectional view showing the vibration isolator in normal load carrying position.

Figure 2 is a similar view of the vibration isolator disassembled from the supporting structure showing its condition when unloaded.

Figure 3 is a view similar to Figure 1 showing the condition of the isolator under application of an upward load to the supported structure.

Figure 4's a view similar to Figure 3 showing the method'o'f disassembling the supported structure from the supporting structure.

Figure 5 is a view similar to Figure 1 showing a modification in the mechanical arrangement.

Figure 6 shows another embodiment with modified resilient-element.

Figure 1 illustrates a preferred embodiment of my invention in which the isolator lll, comprised of rubber or other resilient material, is formed of a substantially hollow spherical shape Il having an aperture at its upper end and a depending cylindrical part i3 at its lower end. The centerv pin I4 is rigidly attached to the supported structure I6 and extends downwardly through the isolator I0. The upper end of the pin M fits snugly within the aperture in the isolator. The load of the supported structure IB is transmitted to the vsupporting structure I1 through the isolator, the sphere-like portion of the isolator bulging'outwardly as the vertical load is applied to its Aupper end. The lower cylindrical part I3 of the isolator fits snugly within the aperture IS in the supporting structure I'I and is spaced from the pin I4. The pin I4 terminates at its lower end in a downwardly and outwardly increasing section 20 whose maximum diameter is slightly less than the diameter of the aperture I9 in the supporting structure I'I.

The method Aof v,assembling the isolator is illustrated in Figure 12. The yassembled rubberpart I and :center pin I4 are attached to the supported structure I6. When unloaded, the lower end of the rubber part is slightly compressed against the ared part 20 of the center ,pin 'LLL This assembly is then inserted into the aperture I9 vin the supporting structure l'I `andrtltle application of the load depresses the ared surface of the center pin slightly below .-:the lcwerledge of the rubber part. When in this condition .the device functions as a vibration isolator and the load 'is carried entirely `by the sphere-like rubber part. 'The lsupported structure Hi thus free to lmoveiin any jdirectionrelativeto the supporting structure.

The method of attachment is illustrated by Figure 3. Any attempt 'to `remove `the -rubber part I0 from the supporting structure Ill 'by an upward rforce` on the supported vstructure I 6 vresults in trapping the lower end '22 y of the rubber part between the vflared part 220 of `the center -pin Id and the supporting Ystructure I-1 This effectively lprevents -its removal from `vthe aperture I 9 and provides an attachment yof great strength between the supporting (Il) yand ysupported (i6) structures.

"The-.method of -eiecting the removal lis illustrated by Figure 4. The lower or cylindrical-part I 3 of the rubber piece -I 0 `mayibefwitlfldrawn vfrom the aperture I9 in the lsupporting structure -I'I before -the `center pin I 4 pulled upwardly' thereby `making possible 'theAremoval-of the pin. One method of removingstheoylindricalpart I3 from the aperture i9 is by-app'lying janvupward force to the lower side of the `sphere H by 'thelngers as illustrated in Figure 4.

Figure v illustrates a slightly diierent .mechanical -detail in which fthe center .pin v25 'takes the form of a sleeve 26 with a ared lowerend 21 andfwhich is held inplacebyfa fla-t head :screw 28 inserted through #the sleeve 26 :and retained at its upper end by a'nut229-orother fastener.

In -the Vmodification -shown in `Figure .6, .the resilient element 30 embodies .a hemispherical upper -part 31| which 4flexes-i-to:permit horizontal and vertical movementof the supported rvstructure '33 with respect to the -supportingstructure 34. The cylindrical `lower `4part 36 protnudes through an aperture 1in lthe supporting-structure 34. The -cylindrical part 36 :terminates 1in an finwarclly projecting ange lf3.1 -which 'functions Ato space the center pin or bolt 139 ffrom theibodyof the cylindrical part'36. vv'The"embodiment-ofthe invention illustrated linfligure '6 functions Lin the manner shown `in 'Figures -3 and 4 with respect to retention in rand removal from the supporting structure.

The accompanying drawings illustrate :the preferred form of the invention, although it is -to be understood that the invention is not limited to the exact details of Aconstructiontshown and described; as -it is obvious that various modifications thereof, withinfthe scope `rof lthe claims, @will occur to persons skilled in the-art.

AI claim:

1 In a vibration isolating assembly, the combination of va `wooden supporting member, fa, :sup-

ported member, a vibration isolator comprising a hollow, substantially spherical p-art made of resilient material and interposed between said members, said part being loaded in compression by the weight of said supported member, and a depending tubular portion formed integral with said part and extending substantially through an aperture in said supporting member, and a rigid stud attached to said supported ,member and vvextending through said part and said por- On, said stud terminating in a downwardly and an outwardly aring enlargement 'arranged to be olitaof `contact with said portion when the resilient ,part ofthe isolator is deiiected and ar- ;rangedjgoslightly expand the lower end of said portion when the resilient part of the isolator @is substantially fzundeiiected.

2. a Vibration isolating assembly, the combination of substantially parallel supporting and supported members, a vibration isolator comprising l.fi-hollow, substantially spherical part made of resilient vmaterial and interposedsbetween said members, -said vpartbeing lloaded in compression by `Athe weight of the upper member. and a depending tubular portion formed integral with said part and extending substantially through an aperture in the lower member, `and a rigid stud :attached to the 'upper member and-extendingfthroughsaid lpart and said portion, said stud terminating in an outwardly ilaringA enlargement arranged :to be =out of contact .withsaid portion when the resilient par-t ofthe isolatoris deflected and arranged to slightly expand 'the lower VLend of said portion when the resilient -pa-rt of *the isolator is `substantially undelected- 3. Thecombination Vofsupporting and supportedfmembers, a-vibrationisolator interposed therebetween,andmeans attached to oneof said memberssaid yisola-tor* comprising a yresilient part interposed-between sai-d membersand. aportion extending .through Van-aperture in the other of Asaid members-saidfportionhavinganopeningthrough which `said means extends, an enlargement o n said --means adjacent the outer -end of said "portion, said :enlargement vbeing :arranged to pass through -said faperture, the vdimensions vof said combination being such that said enlargement isengaged Iwith said portion when -said resilient part is substantially `lundeilected, and is disengaged ffrom `said portion when said vresilient part is deflected.

A4. lThe'con'lbination'of supporting fand supported members, a vibration isolator interposed therebetween, and means attached to said supported member, said isolator comprising a resilient -part interposed between said members and va lportion extending through anrapertureiin said :supporting member, said yportionhaving an opening through which isaid means `extends, yan enlargement on saidmeans adjacent theouter-end of said portion, said enlargement being arranged to pass through said aperture, "the dimensions of said icombination being `such :that said enlargement is engaged with .said -portion when-said resilient ,part is :substantially -undeected, and is disengaged from said portion when said resilient part isdeected. y

i5. The combination of supporting and supportedzmembers, aavibration isolator interposed .therebetween` -and a stud'attached'to one of said -members, :said isolator comprising a resilient Jpart interposed lbetween saidmembers and a portionaextending jthroughlan 1 aperture in Ithe other of said members, said portion having an opening through Whichsaidfstudiextends,and Ltermina-tesinan outwardly aring enlargement adjacent the outer end of said portion, the dimensions of said combination being such that said enlargement is engaged with said portion when said resilient part is substantially undeflected, an-d is disengaged from said portion when said resilient part is delect'ed.

6. A vibration isolator adapted for use with supporting and supported members comprising, a resilient part arranged to be interposed between said members and a portion arranged to protrude through an aperture in one of said members, said isolator having an opening extending therethrough, and being adapted for use with means attached to the other of said members and extending through said opening, said means having an enlargement which is engaged with the outer end of said portion when the resilient part of the isolator is substantially undeected and disengaged when the resilient part is deflected.

'7. A vibration isolator adapted for use with supporting and supported members comprising, a hollow substantially spherical resilient part arranged to be interposed between said members and a tubular portion arranged to protrude through an aperture in one of said members, said isolator being adapted for use with means attached to the other of said members and extending through said spherical part and said tubular portion, said means having an enlargement which is engaged with the outer end of said portion when the resilient part of the isolator is substantially undeflected and disengaged when the resilient part is deected.

8. A Vibration isolator adapted for use with supporting and supported members, comprising a resilient part arranged to be interposed between said members and a portion arranged to protrude through an aperture in said supporting member, said isolator having an opening extending therethrough and being adapted for use with depending means attached to said supported member and extending through said opening, said means having an enlargement which is engaged with the lower end of said portion when the resilient part of the isolator is substantially undeected and disengaged when the resilient part is deected.

9. A vibration isolator adapted for use with supporting and supported members comprising, a resilient part arranged to be interposed between said members and a portion arranged to protrude through an aperture in one of said members, said isolator having an opening extending therethrough and being adapted for use with a rigid stud attached to the other of said members and extending through said opening, said means having an outwardly flaring enlargement at its end which is engaged with the outer end of said portion when the resilient part of the isolator is substantially undeflected and disengaged when the resilient part is deflected.

ERVIN PIETZ.

REFERENCES CITED The following references are of record in the i'lle of this patent:

'UNITED STATES PATENTS- Number Name Date 1,935,202 Chamberlain et al. Nov. 14, 1933 FOREIGN PATENTS Number Country Date 143,349 Switzerland Jan. 16, 1931 

